HorizontalPaging / src / com.example.android.horizontalpaging /

MainActivity.java

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package com.example.android.horizontalpaging;
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import android.app.ActionBar;
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import android.app.FragmentTransaction;
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import android.os.Bundle;
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import android.support.v4.app.Fragment;
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import android.support.v4.app.FragmentActivity;
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import android.support.v4.app.FragmentManager;
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import android.support.v4.app.FragmentPagerAdapter;
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import android.support.v4.view.ViewPager;
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import android.view.LayoutInflater;
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import android.view.View;
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import android.view.ViewGroup;
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import android.widget.TextView;
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import java.util.Locale;
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public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
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    /**
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     * The {@link android.support.v4.view.PagerAdapter} that will provide
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     * fragments for each of the sections. We use a
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     * {@link android.support.v4.app.FragmentPagerAdapter} derivative, which
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     * will keep every loaded fragment in memory. If this becomes too memory
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     * intensive, it may be best to switch to a
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     * {@link android.support.v4.app.FragmentStatePagerAdapter}.
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     */
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    SectionsPagerAdapter mSectionsPagerAdapter;
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    /**
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     * The {@link ViewPager} that will host the section contents.
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     */
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    ViewPager mViewPager;
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    /**
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     * Create the activity. Sets up an {@link android.app.ActionBar} with tabs, and then configures the
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     * {@link ViewPager} contained inside R.layout.activity_main.
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     *
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     * <p>A {@link SectionsPagerAdapter} will be instantiated to hold the different pages of
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     * fragments that are to be displayed. A
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     * {@link android.support.v4.view.ViewPager.SimpleOnPageChangeListener} will also be configured
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     * to receive callbacks when the user swipes between pages in the ViewPager.
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     *
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     * @param savedInstanceState
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     */
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    @Override
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    protected void onCreate(Bundle savedInstanceState) {
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        super.onCreate(savedInstanceState);
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        // Load the UI from res/layout/activity_main.xml
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        setContentView(R.layout.sample_main);
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        // Set up the action bar. The navigation mode is set to NAVIGATION_MODE_TABS, which will
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        // cause the ActionBar to render a set of tabs. Note that these tabs are *not* rendered
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        // by the ViewPager; additional logic is lower in this file to synchronize the ViewPager
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        // state with the tab state. (See mViewPager.setOnPageChangeListener() and onTabSelected().)
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        final ActionBar actionBar = getActionBar();
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        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
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        // Create the adapter that will return a fragment for each of the three primary sections
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        // of the app.
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        mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
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        // Set up the ViewPager with the sections adapter.
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        mViewPager = (ViewPager) findViewById(R.id.pager);
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        mViewPager.setAdapter(mSectionsPagerAdapter);
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        // When swiping between different sections, select the corresponding tab. We can also use
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        // ActionBar.Tab#select() to do this if we have a reference to the Tab.
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        mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
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            @Override
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            public void onPageSelected(int position) {
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                actionBar.setSelectedNavigationItem(position);
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            }
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        });
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        // For each of the sections in the app, add a tab to the action bar.
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        for (int i = 0; i < mSectionsPagerAdapter.getCount(); i++) {
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            // Create a tab with text corresponding to the page title defined by the adapter. Also
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            // specify this Activity object, which implements the TabListener interface, as the
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            // callback (listener) for when this tab is selected.
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            actionBar.addTab(
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                    actionBar.newTab()
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                            .setText(mSectionsPagerAdapter.getPageTitle(i))
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                            .setTabListener(this));
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        }
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    }
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    /**
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     * Update {@link ViewPager} after a tab has been selected in the ActionBar.
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     *
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     * @param tab Tab that was selected.
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     * @param fragmentTransaction A {@link android.app.FragmentTransaction} for queuing fragment operations to
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     *                            execute once this method returns. This FragmentTransaction does
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     *                            not support being added to the back stack.
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     */
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    @Override
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    public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
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        // When the given tab is selected, tell the ViewPager to switch to the corresponding page.
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        mViewPager.setCurrentItem(tab.getPosition());
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    }
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    /**
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     * Unused. Required for {@link android.app.ActionBar.TabListener}.
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     */
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    @Override
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    public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
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    }
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    /**
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     * Unused. Required for {@link android.app.ActionBar.TabListener}.
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     */
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    @Override
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    public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
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    }
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    /**
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     * A {@link FragmentPagerAdapter} that returns a fragment corresponding to
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     * one of the sections/tabs/pages. This provides the data for the {@link ViewPager}.
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     */
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    public class SectionsPagerAdapter extends FragmentPagerAdapter {
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        public SectionsPagerAdapter(FragmentManager fm) {
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            super(fm);
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        }
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        /**
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         * Get fragment corresponding to a specific position. This will be used to populate the
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         * contents of the {@link ViewPager}.
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         *
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         * @param position Position to fetch fragment for.
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         * @return Fragment for specified position.
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         */
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        @Override
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        public Fragment getItem(int position) {
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            // getItem is called to instantiate the fragment for the given page.
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            // Return a DummySectionFragment (defined as a static inner class
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            // below) with the page number as its lone argument.
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            Fragment fragment = new DummySectionFragment();
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            Bundle args = new Bundle();
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            args.putInt(DummySectionFragment.ARG_SECTION_NUMBER, position + 1);
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            fragment.setArguments(args);
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            return fragment;
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        }
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        /**
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         * Get number of pages the {@link ViewPager} should render.
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         *
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         * @return Number of fragments to be rendered as pages.
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         */
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        @Override
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        public int getCount() {
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            // Show 3 total pages.
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            return 3;
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        }
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        /**
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         * Get title for each of the pages. This will be displayed on each of the tabs.
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         *
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         * @param position Page to fetch title for.
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         * @return Title for specified page.
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         */
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        @Override
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        public CharSequence getPageTitle(int position) {
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            Locale l = Locale.getDefault();
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            switch (position) {
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                case 0:
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                    return getString(R.string.title_section1).toUpperCase(l);
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                case 1:
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                    return getString(R.string.title_section2).toUpperCase(l);
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                case 2:
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                    return getString(R.string.title_section3).toUpperCase(l);
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            }
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            return null;
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        }
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    }
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    /**
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     * A dummy fragment representing a section of the app, but that simply displays dummy text.
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     * This would be replaced with your application's content.
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     */
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    public static class DummySectionFragment extends Fragment {
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        /**
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         * The fragment argument representing the section number for this
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         * fragment.
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         */
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        public static final String ARG_SECTION_NUMBER = "section_number";
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        public DummySectionFragment() {
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        }
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        @Override
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        public View onCreateView(LayoutInflater inflater, ViewGroup container,
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                Bundle savedInstanceState) {
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            View rootView = inflater.inflate(R.layout.fragment_main_dummy, container, false);
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            TextView dummyTextView = (TextView) rootView.findViewById(R.id.section_label);
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            dummyTextView.setText(Integer.toString(getArguments().getInt(ARG_SECTION_NUMBER)));
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            return rootView;
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        }
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    }
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}